Exhaust gas diffuser

ABSTRACT

An exhaust gas-cooling device for use on an exhaust gas conveyance system of a vehicle to emit exhaust gases from an engine to an outlet includes a pipe defining an exhaust gas passageway that is in fluid communication with the engine, and a diffuser in fluid communication with the exhaust gas passageway. The diffuser is configured for receiving the pipe, and has a body defining an outlet of the exhaust gas passageway to the ambient, and a diffusing structure disposed on the body generally opposite the outlet. The diffusing structure has a separating structure configured for receiving and diverting the flow of exhaust gas emitted from the pipe, and a guiding structure configured for guiding the diverted flow of exhaust gas along the body to the outlet.

BACKGROUND OF THE INVENTION

The present invention relates generally to exhaust gas conveyancesystems in vehicles. More specifically, the present invention relates toan exhaust gas-cooling device for reducing the temperature of exhaustgases emitted from a vehicle's engine.

Exhaust gas conveyance systems on vehicles frequently emit exhaust gaseswith extremely high temperatures. The high temperatures can be achievedfrom routine engine operation, particularly on larger vehicles. Further,the high temperatures can also be achieved during a regeneration event,where collected particulate matter that is trapped in a particulatefilter is oxidized. During both routine operation and regenerationevents, the vehicle's operating environment can be subjected toundesirable high temperatures.

Thus, there is a need for an exhaust gas-cooling device that can beeasily provided on most exhaust gas conveyance systems with littlemodification to the existing exhaust gas conveyance system.

BRIEF SUMMARY OF THE INVENTION

The above-listed needs are met or exceeded by the present exhaustgas-cooling device for use on an exhaust gas conveyance system of avehicle to emit exhaust gases from an engine to an outlet. The exhaustgas cooling device includes a pipe defining an exhaust gas passagewaythat is in fluid communication with the engine and a diffuser in fluidcommunication with the exhaust gas passageway. The diffuser isconfigured for receiving the pipe, and has a body defining an outlet ofthe exhaust gas passageway to the ambient, and a diffusing structuredisposed on the body generally opposite the outlet. The diffusingstructure has a separating structure configured for receiving anddiverting the flow of exhaust gas emitted from the pipe, and a guidingstructure configured for guiding the diverted flow of exhaust gas alongthe body to the outlet.

Also provided is a diffuser for use on an exhaust gas conveyance systemof a vehicle having a pipe defining an exhaust gas passageway to emitexhaust gases from an engine to an outlet. The diffuser includes a bodyin fluid communication with the pipe and defining an outlet of theexhaust gas passageway to an ambient. The body is formed of aconductive, corrosion resistant material. The diffuser also includes adiffusing structure disposed on the body generally opposite the outlet,where the diffusing structure has a separating structure configured forreceiving and diverting the flow of exhaust gas emitted from the pipe,and a guiding structure adjacent the diffusing structure configured forguiding the diverted flow of exhaust gas along the body to the outlet.

An alternate embodiment of exhaust gas-cooling device for use on anexhaust gas conveyance system of a vehicle to emit exhaust gases from anengine to an outlet includes a pipe defining an exhaust gas passagewaythat is in fluid communication with the engine. The cooling device alsoincludes a generally rectangular shaped diffuser in fluid communicationwith the exhaust gas passageway and configured for receiving the pipe.The diffuser includes a body defining an outlet of the exhaust gaspassageway to the ambient, where the body has an upstream surfaceconfigured for receiving the pipe. A diffusing structure is disposed onthe body generally opposite the outlet. The diffusing structure has agenerally concavely shaped separating structure configured for receivingand diverting the flow of exhaust gas emitted from the pipe, and twogenerally convexly shaped guiding structures disposed on each side ofthe separating structure and configured for guiding the diverted flow ofexhaust gas along the body to the outlet.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of an exhaust gas cooling device;

FIG. 2 is a side view of the exhaust gas cooling device;

FIG. 3 is a plan view of the exhaust gas cooling device; and

FIG. 4 is a top view of the exhaust gas cooling device.

DETAILED DESCRIPTION OF THE INVENTION

Referring now to FIGS. 1-3, an exhaust gas-cooling device is depictedgenerally at 10, and includes an exhaust gas conveyance system ortailpipe 12 and a diffuser 14. The exhaust gas conveyance system 12 ismounted on a vehicle (not shown) forming an exhaust gas passageway 16which routes the exhaust gases from the vehicle's engine (not shown) toa remote location where the gases can be expelled into the ambient.

In the direction of flow of the exhaust gases, the exhaust gasconveyance system 12 can incorporate aftertreatment devices (not shown),such as an oxidation catalyst member (not shown) and a particulatefilter (not shown). The oxidation catalyst member oxidizes unburned fueland oil to reduce harmful emissions, and the particulate filter removesparticulate matter from the exhaust gases. When particulate matter getstrapped in the particulate filter, a periodic or continuous regenerationevent oxidizes the collected particulate matter. The regeneration eventtypically produces large amounts of heat, which increases the heat ofthe exhaust gases.

The diffuser 14 of the exhaust gas-cooling device 10 is locateddownstream of the particulate filter. For purposes of this application,the terms “downstream” and “upstream” refer to the direction of gas flowfrom the engine out into the ambient.

As shown in FIG. 3, an interior portion 18 of the tailpipe 12 isreceived in the diffuser 14 and an exterior portion 20 extends outwardlyfrom the diffuser. The distal end 22 of the exterior portion 20 definesa tailpipe outlet 22 for exhaust gases. Preferably, the tailpipe 12 isgenerally cylindrical and generally linear at the exterior portion 20and further, the tailpipe is generally cylindrical and curved at theinterior portion 18. In the preferred embodiment, the interior portion18 forms an angle θ with respect to the exterior portion 20, wherein theangle θ is preferably less than 90-degrees. In the most preferredembodiment, the angle θ is about 45-degrees.

The exhaust gas-cooling device 10 has a generally rectangular or“box”-shaped body 24 for receiving the exhaust gases. The body 24includes an upstream surface 26 which receives the tailpipe 12, adownstream surface 28 generally opposite the upstream surface, and afirst and second side surfaces 30, 32. The body 24 is preferably made ofa conductive material that is corrosion resistant. More preferably, thebody 24 is made of a metal, such as stainless steel.

The upstream surface 26, downstream surface 28, and side surfaces 30, 32of the body 24 define an exhaust gas passageway outlet 34 to theambient. In the preferred embodiment, the entire bottom portion of thebody 24 is open to the ambient, however, it is contemplated that thebottom portion may be partially enclosed with an aperture being open tothe ambient. Additionally, other configurations of outlet 34 arecontemplated.

The exhaust gas-cooling device 10 is configured for reducing the bulktemperature of the exhaust gases using a diffusing structure 36. In thepreferred embodiment, the diffusing structure 36 is attached to orintegral with the body 24 and forms a top portion 38 of the body. Thediffusing structure 36 has a separating structure 40 running along atleast a portion of the length “L” of the body 24, and a guidingstructure 42 on each side of the separating structure. Preferably, theseparating structure 40 is generally concavely contoured (as viewed fromthe exterior of the diffuser 14) and runs the entire length “L” of thebody 24. The separating structure 40 is configured to receive theexhaust gas flow, and to divert the flow. Preferably, the concavecontours of the separating structure 40 transition into the generallyconvex contours (as viewed from the exterior of the diffuser 14) of theguiding structure 42. The guiding structures 42 run parallel to theseparating structure 40, and in cross-section, the top portion 38 of thebody 24 has an alternating “ridge-groove-ridge” shape.

In the preferred embodiment, the exhaust gas passageway 16 for the flowof exhaust gas is through the exterior portion 20 and into the interiorportion 18 of the tailpipe 12. In the interior portion 18, the exhaustgas is directed toward the diffusing structure 36, and out of thetailpipe outlet 22 adjacent to the separating structure 40. When theflow exits the tailpipe outlet 22, it has an angle of incidence β on theseparating structure 40. Preferably, the angle of incidence β is lessthan 90-degrees, and more preferably, the angle of incidence β is about45-degrees. The exhaust gas impacts the diffusing structure 36 at theangle of incidence β, and the separating structure 40 diffuses the flowmomentum of the gases by abruptly changing the direction of flow.

While the preferred embodiment includes an angled tailpipe 12configuration, it is contemplated that a linear pipe or any otherconfiguration of tailpipe 12 can also be used. However, it is preferredthat the angle of incidence β of the exhaust gas flow onto the diffusingstructure be less than 90-degrees.

The flow impacts the separating structure 40 and diverts the flow toboth sides of the separating structure 40 and to the guiding structures42 as indicated by the arrows “F” on FIG. 1. The arrows “F” illustratesome example flow lines, however the flow path of the exhaust gas shouldnot be limited to the arrows “F”.

Preferably, the separating structure 40 gradually transitions into theguiding structure 42, and the guiding structure 42 preferably graduallytransitions into the side surfaces 30, 32. In this configuration, theexhaust gas is gradually directed along the body 24 and to the exhaustgas passageway outlet 34 where it can exit to the ambient.

The separating structure 40 and the guiding structure 42 diffuse themomentum of the exhaust gas. With the exhaust gas passageway outlet 34disposed opposite the diffusing structure 36, the exhaust gas mixes withthe ambient air. The impact of the exhaust gas onto the diffusingstructure 36 together with the mixing of the ambient air prevents theemission of a developed jet of hot exhaust gas from the exhaust gaspassageway 16.

Additionally, the body 24 of the diffuser 14 creates a partial chamberwhere the exhaust gas is stagnated. Since the gas is stagnant, heat isemitted from the exhaust gas to the metal body 24. The body 24 acts as aheat shield to conduct the heat over a large, uniform surface, where theheat can be redistributed more gradually to the ambient.

Further, the guiding structure 42 of the diffuser guides the flow ofexhaust gases along a large metal surface of the body 24. This allowsthe exhaust flow to emit its heat energy through convection to the metalhousing. While the preferred embodiment of guiding surface 42 includestwo convexly contoured surfaces, any surface that permits the flow ofgas along a large metal surface to the exhaust gas passageway 16 iscontemplated.

The present exhaust gas-cooling device 10 further reduces thetemperature of the exhaust gases as compared to conventional devices.Further, the configuration of the diffuser makes it easy to retrofitonto existing exhaust gas conveyance systems by replacing theconventional tailpipe with the tailpipe 12 and the diffuser 14 of thepresent invention. Further still, it is contemplated that the diffuser14 include a separate interior pipe that is configured to connect to thetailpipe 12 of the vehicle.

While particular embodiments of the present exhaust gas-cooling device110 have been shown and described, it will be appreciated by thoseskilled in the art that changes and modifications may be made theretowithout departing from the invention in its broader aspects and as setforth in the following claims.

1. An exhaust gas-cooling device for use on an exhaust gas conveyancesystem of a vehicle to emit exhaust gases from an engine to an outlet,comprising: a pipe defining an exhaust gas passageway that is in fluidcommunication with the engine; a diffuser in fluid communication withsaid exhaust gas passageway and configured for receiving said pipe, saiddiffuser comprising: a body defining an outlet of said exhaust gaspassageway to an ambient; a diffusing structure disposed on said bodygenerally opposite said outlet, said diffusing structure having aseparating structure configured for receiving and diverting the flow ofexhaust gas emitted from said pipe, and a guiding structure configuredfor guiding the diverted flow of exhaust gas along said body to saidoutlet.
 2. The exhaust gas-cooling device of claim 1 wherein said bodycomprises an upstream surface that receives said pipe, and a downstreamsurface generally opposite said upstream surface.
 3. The exhaustgas-cooling device of claim 2 wherein said body comprises first andsecond side surfaces.
 4. The exhaust gas-cooling device of claim 1wherein said body is formed of a conductive, corrosion resistantmaterial.
 5. The exhaust gas-cooling device of claim 4 wherein said bodyis formed of stainless steel.
 6. The exhaust gas-cooling device of claim1 wherein said separating structure is generally concavely contoured. 7.The exhaust gas-cooling device of claim 1 wherein said guiding structureis disposed adjacent said separating structure and comprises at leastone generally convex contour.
 8. The exhaust gas-cooling device of claim1 wherein said guiding structure and said separating structure aregenerally parallel and form a “ridge-groove-ridge” shape in profile. 9.The exhaust gas-cooling device of claim 1 wherein said pipe has aninterior portion disposed within said body, and an exterior portiondisposed outside of said body, wherein said interior portion is angledwith respect to said exterior portion.
 10. The exhaust gas-coolingdevice of claim 9 wherein said interior portion of said pipe defines apipe outlet for emitting exhaust gases into said diffuser.
 11. Theexhaust gas-cooling device of claim 1 wherein said diffusing structureis configured to receive the exhaust gases at an angle of incidence ofless than 90-degrees.
 12. A diffuser for use on an exhaust gasconveyance system of a vehicle having a pipe defining an exhaust gaspassageway to emit exhaust gases from an engine to an outlet, saiddiffuser comprising: a body in fluid communication with the pipe anddefining an outlet of the exhaust gas passageway to an ambient, saidbody formed of a conductive, corrosion resistant material; a diffusingstructure disposed on said body generally opposite said outlet, saiddiffusing structure having a separating structure configured forreceiving and diverting the flow of exhaust gas emitted from the pipe,and a guiding structure adjacent said diffusing structure configured forguiding the diverted flow of exhaust gas along said body to said outlet.13. The diffuser of claim 12 wherein said body comprises an upstreamsurface that is configured to receive the pipe, and a downstream surfacegenerally opposite said upstream surface.
 14. The diffuser of claim 13wherein said body comprises first and second side surfaces, and whereinsaid upstream surface, said downstream surface, said first surface andsaid second surface define said outlet of the exhaust gas passageway.15. The diffuser of claim 12 wherein said separating structure isgenerally concavely contoured.
 16. The diffuser of claim 12 wherein saidguiding structure is disposed adjacent said separating structure andcomprises at least one generally convex contour.
 17. The diffuser ofclaim 12 wherein said separating structure extends at along at least aportion of the length of said body.
 18. The diffuser of claim 12 whereinsaid body further comprises an interior pipe disposed in the interior ofsaid body, said interior pipe configured to be in fluid communicationwith the pipe to define the exhaust gas passageway.
 19. The diffuser ofclaim 18 wherein said interior pipe directs the exhaust gas at saiddiffusing structure at an angle of incidence of less than 90-degrees.20. An exhaust gas-cooling device for use on an exhaust gas conveyancesystem of a vehicle to emit exhaust gases from an engine to an outlet,comprising: a pipe defining an exhaust gas passageway that is in fluidcommunication with the engine; a generally rectangular shaped diffuserin fluid communication with said exhaust gas passageway and configuredfor receiving said pipe, said diffuser comprising: a body defining anoutlet of said exhaust gas passageway to an ambient, said body having anupstream surface configured for receiving said pipe; a diffusingstructure disposed on said body generally opposite said outlet, saiddiffusing structure having a generally concavely shaped separatingstructure configured for receiving and diverting the flow of exhaust gasemitted from said pipe, and two generally convexly shaped guidingstructures disposed on each side of said separating structure andconfigured for guiding the diverted flow of exhaust gas along said bodyto said outlet.